1. Field of the Invention
This invention relates to an oxidation exhaust trap for filtering a particulate product of a first gas contacted with a gaseous oxidizing agent. More specifically, this invention relates to an oxidation exhaust trap for filtering. silica resulting from the oxidation of silane with air.
2. Description of the Related Art
Exhaust gases which contain silane and must be subjected to cleaning are being produced today in many branches of industry, as for example in the production of silicon compounds, in the packing of silicon compounds, in the production and bottling of silane-containing gas mixtures, and in the production of semiconductors.
Conventional methods of disposal, such as scrubbing, burning, or washing in wash towers present great problems with regard to the expense, maintenance, and complexity of the equipment necessary to carry out these methods.
Of these methods, scrubbing the gases containing the silane is most popular. while this method has its benefits, it requires complex and expensive apparatus. Furthermore, the maintenance of the scrubber caused by the silane containing gases is very costly and time consuming. The silane tends to clog the scrubber""s exhaust system filters. Thus to maintain the scrubber properly, the filters need to be cleaned periodically. Making matters worse is that the processes which feed the scrubber, including those which produce the silane gas, must be shut down while the maintenance is performed.
Therefore, it is an object of the present invention to provide an exhaust trap for filtering a particulate product of a gas which is inexpensive to operate, fabricate, and maintain.
It is another object of the present invention to provide a lightweight exhaust trap for filtering a particulate product of a gas.
It is yet another object of the present invention to provide an exhaust trap for filtering a particulate product of a gas which operates at room temperature.
Accordingly, a first embodiment of an oxidation exhaust trap for filtering a particulate product of a first gas contacted with a gaseous oxidizing agent is provided. The oxidation exhaust trap comprises a vessel having an interior cavity, a first inlet in communication with the interior cavity for introduction of the first gas into the interior cavity, and a second inlet in communication with the interior cavity for introduction of the gaseous oxidizing agent into the interior cavity, the gaseous oxidizing agent mixing with the first gas thereby causing oxidation of the first gas for producing the particulate product suspended in a gaseous product. The vessel further having an outlet in communication with the interior cavity. A filter is disposed in the interior cavity for filtering the particulate product from the gaseous product which is then exhausted through the outlet.
In a second embodiment of the present invention an oxidation exhaust trap for filtering a particulate product of a first gas contacted with a gaseous oxidizing agent is provided. The oxidation exhaust trap comprises a vessel having an interior cavity. The interior cavity has a first and a second part in communication with each other. A first inlet is provided which is in communication with the first part of the interior cavity for introduction of the first gas into the first part of the interior cavity. A second inlet is provided which is in communication with the first part of the interior cavity for introduction of the gaseous oxidizing agent into the first part of the interior cavity, the gaseous oxidizing agent mixing with the first gas. The mixing of the first gas with the oxidizing agent causes the oxidation of the first gas in the first part of the interior cavity, wherein the particulate product is produced suspended in a gaseous product. The vessel also has an outlet in communication with the second part of the interior cavity. A first filter is disposed in the first part of the interior cavity for filtering the particulate product of a predetermined size from the gaseous product. A second filter is disposed in the second part of the interior cavity for filtering the remaining particulate product from the gaseous product which is then exhausted through the outlet.
In a preferred version of the first and second embodiments of the oxidation exhaust trap of the present invention, the first gas is silane, the particulate product is silica, and the gaseous oxidizing agent is air.
In yet another preferred version of the first and second embodiments, the vessels are arranged in series wherein the filters disposed in their respective vessels filter successively smaller particulates from the gaseous product before the gaseous product is exhausted through the outlet of the last vessel in the series.
Other aspects of the present invention are methods for filtering a particulate product of a first gas contacted with a gaseous oxidizing agent and a system for the same.